代码

int binary_search(const unsigned *a, int n, unsigned x)
{
	const unsigned *b[2] = {a, a + n};
	do
	{
		const unsigned *mid = (unsigned *)(((int)b[0] + (int)b[1]) / 2);
		b[*mid > x] = mid;
	}
	while (b[0] + 1 != b[1]);
	return b[0] - a;
}

评测结果